Scientists know a lot about how we control our food intake, but not yet enough to develop targeted treatments that have a dramatic impact on curtailing obesity, anorexia, and other eating disorders. Newly published Foundation-funded research offers new insights on the brain circuitry involved in food intake that offers promise for more targeted and effective treatments.
A research team at California Institute of Technology (Caltech) identified a population of neurons in the central amygdala region of the brain (a brain structure known more for its role in emotion regulation) that controls feeding behavior. “Identifying these neurons helps us better understand the inhibitory control of feeding, and might someday lead to better treatments for eating disorders such as anorexia or bulimia, or for obesity,” says first author Haijiang Cai, Ph.D., 2010 NARSAD Young Investigator Grantee.
The research was led by two-time NARSAD Distinguished Investigator Grantee (1999, 2007) David J. Anderson, Ph.D., and was published online July 27th in Nature Neuroscience. Drs. Cai, Anderson and colleagues at Caltech sought to better understand a much-debated role of a part of the amygdala called the central nucleus in controlling food intake. In experiments with living, “behaving” mice, the researchers were able to pinpoint a sub-region within the central nucleus part of the amygdala that acts as a kind of switchboard, or node, for processing signals coming from different parts of the brain, all pertaining to “stop eating” cues.
Using the new technology optogenetics, they found that activation of a set of neurons within this subregion in mice caused them to abruptly stop eating. “This is not because they are anxious or afraid,” explains Dr. Cai. “These neurons seem to mediate the effect of several kinds of inhibitory influences on food intake, including satiety, bitter taste, and visceral malaise (i.e., feeling sick to your stomach). Thus we think they are a central node that integrates the influences of multiple 'anorexigenic' (feeding-inhibitory) signals, and relays this information to inhibit other brain centers that normally promote feeding.”
Before this study, scientists debated whether such signals were processed separately, in parallel, or whether there was some node or switchboard that served as a central place to coordinate the “don’t eat” response. The technology optogenetics offers unprecedented insight into brain circuitry by allowing researchers to turn specific neurons “on” and “off” and observe the effect on behavior—in this study, the new insight gained may lead to new treatment development for eating disorders.
Read about this research in The New York Times.